EasyJet has posted half-year losses of £57.5m to 31 March, blaming sharply rising oil costs.

The dip is a sizeable increase compared to the £17.1m loss for the comparable period last year, but the carrier remains adamant that its long-term business model is robust enough to weather the storm.

Total revenue grew 24% to £892.2m, while the absorption of GB Airways saw passenger numbers increase 15% to 18.9m with a load factor of 81% - the same as for 2007.

“Oil remains the biggest challenge and uncertainty – the price of jet fuel has risen 35% during the past three months and is now 80% higher than last year,” said easyJet chief executive Andy Harrison.

“Nobody knows how much of this increase is driven by short term financial speculation and how much is a longer term sustainable increase. What is certain is that if these fuel increases are maintained, many of our weaker competitors will disappear or downsize and easyJet will emerge even stronger.”

Despite the loss, the low-cost carrier is keen to emphasise that the £57.5m includes a one-off payment of £9.1m for the merger with GB Airways, which now makes Gatwick easyJet’s largest base and has allowed it to start services from Manchester.

The GB Airways acquisition is also expected to deliver £20m of synergy benefits and integration of supplier contracts, while the fusion now gives easyJet 29% of departing passengers at Gatwick.

EasyJet has long targeted the business traveller and says that the GDS roll-out announced earlier is now ‘complete in the UK, Ireland, Switzerland, Portugal, Belgium, Spain and Italy.’

Progress has also been made it says, in securing adoption of the GDS with major business travel management companies.